CCSM3对太平洋年代际振荡的敏感性试验

Decadal variability in the Pacific as simulated by CCSM3

利用NCAR的CCSM3模式进行控制试验和1870—1999年的130 a模拟试验(敏感性试验),与相应的再分析资料进行对比,分析了太平洋海区的海温变化趋势和北太平洋年代际变率的时空结构,并且讨论了CO2对于北太平洋年代际变率的影响。结果表明:CCSM3模式能够模拟出北太平洋年代际变率的主要特征,其空间分布类似于典型的PDO海温异常分布型。特别是考虑了CO2增长变化以后,模式的结果更加接近再分析资料,其时间变化反映了20世纪北太平洋海温异常所经历的3次位相的转变。CO2增长变化,可以使这种太平洋年代际变化的周期增长,并且太平洋这种年代际位相转变也与CO2的变化增长有关。模式在考虑了CO2增长变化以后,双核的位置会偏东偏深,东西方向的温差将减少,也就是说CO2的增长变化,对PDO的位置和强度都有影响。

Using CCSM3 model of NCAR,this study examines the results of control run and 130yr simulation run form year 1870 to 1999.The temperature varying trend of the Pacific Ocean area and the spatial-temporal structure of the North Pacific Decadal Oscillation（PDO） are analyzed by comparing model output with corresponding reanalysis data.The results indicate that the model simulates well many features of the observed PDO,the spatial distribution pattern of sea surface temperature anomaly are similar to the typical PDO.Especially when the trend of CO2 is considered in simulation,the three important phase-changing of SSTA in North Pacific Ocean in the 20th are well reproduced.The position of two core of temperature anomaly in subsurface are more eastern and deeper,and the temperature difference between east and west are reduced.The increasing of CO2 play an important role in elongating the period and phase-changing of simulated PDO,the position and intensity are also affected.